U.S. patent number 7,263,396 [Application Number 10/900,146] was granted by the patent office on 2007-08-28 for ear sensor assembly.
This patent grant is currently assigned to Cardiodigital Limited. Invention is credited to Yunquan Chen, Christopher Grant Denny, Luya Li, Scott Howard Phillips, Rakesh Kumar Sethi, Ming Sun.
United States Patent |
7,263,396 |
Chen , et al. |
August 28, 2007 |
Ear sensor assembly
Abstract
A sensor assembly for monitoring physiological characteristics
interfaces to a subject's ear. The sensor assembly has a projection
that projects into the subject's concha. The projection may have a
notch to accommodate the subject's anti-tragus. A clip connected to
the projection holds a sensor against the subject's lobule. The
sensor may comprise a pulse-oximetry-type sensor.
Inventors: |
Chen; Yunquan (Delta,
CA), Li; Luya (Coquitlam, CA), Sethi;
Rakesh Kumar (Vancouver, CA), Sun; Ming (New
Westminster, CA), Denny; Christopher Grant (Victoria,
CA), Phillips; Scott Howard (Victoria,
CA) |
Assignee: |
Cardiodigital Limited (East
Lothian, GB)
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Family
ID: |
34119088 |
Appl.
No.: |
10/900,146 |
Filed: |
July 28, 2004 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050033131 A1 |
Feb 10, 2005 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60493361 |
Aug 8, 2003 |
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Current U.S.
Class: |
600/340;
600/344 |
Current CPC
Class: |
A61B
5/14552 (20130101); A61B 5/6816 (20130101) |
Current International
Class: |
A61B
5/00 (20060101) |
Field of
Search: |
;600/322,323,340,344 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Winakur; Eric
Assistant Examiner: Berhanu; Etsub
Attorney, Agent or Firm: Oyen Wiggs Green & Mutala
LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. application No.
60/493,361 filed on 8 Aug. 2003.
Claims
What is claimed is:
1. An ear sensor assembly comprising: a projection insertable into
the concha of a subject's ear; a clip connected to the projection,
the clip comprising a first part biased toward a second part; and a
sensor on the first part of the clip, wherein one end of the second
part is connected to the first part, a second end of the second
part is movable toward and away from the first part, the projection
projects from the first part; and wherein the projection is
penetrated by an aperture and comprises a portion of a ring and the
portion of a ring has a radius in the range of 3.5mm to 6mm and a
thickness in the range of 1.5mm to 3mm.
2. An ear sensor assembly according to claim 1 wherein a sensor is
on the second part of the clip.
3. An ear sensor assembly according to claim 1 wherein the first
and second parts of the clip are hingedly connected to one
another.
4. An ear sensor assembly according to claim 1 wherein the first
and second parts of the clip are coupled together by a resilient
member, and the resilient member biases the second end of the
second member toward the first member.
5. An ear sensor assembly according to claim 1 wherein the
projection comprises a half-ring.
6. An ear sensor assembly according to claim 1 wherein the
projection has a surface characterized by a high coefficient of
friction with human skin.
7. An ear sensor assembly according to claim 1 comprising a
removable cover on the projection.
8. An ear sensor assembly according to claim 7 wherein the
removable cover comprises an elastomeric material.
9. An ear sensor assembly according to claim 1 wherein the sensor
comprises a first component on the first part of the clip and a
second component on the second part of the clip.
10. An ear sensor assembly according to claim 9 wherein one of the
first and second components emits radiation and another one of the
first and second components receives the radiation.
Description
TECHNICAL FIELD
The invention relates to physiological sensors which interface to a
subject's ear.
BACKGROUND
There are various circumstances in the health care field where it
is desirable to measure some physiological characteristic of a
subject person and it is convenient to make such measurement using
a sensor which interfaces to the subject's ear.
For example, some known pulse oximetry sensors clip to a subject's
earlobe. An example of one such pulse oximetry sensor is described
in Bukta, U.S. Pat. No. 5,611,337. An example of a heart rate
sensor which clips onto a subject's earlobe is shown in FIG. 3 of
Greubel et al., U.S. Pat. No. 5,237,997. Various types of sensors
may be clipped to a subject's earlobe. The output signals of such
sensors may be used for various purposes including measuring heart
rate, measuring blood oxygen saturation, measuring blood pressure,
measuring temperature, or the like.
Clipping a sensor to a subject's earlobe is convenient. However,
the inventors have identified a number of disadvantages of current
earlobe sensors. These include the following: Some sensors work
best when located in a specific position on a subject's earlobe. A
typical ear sensor can be clipped onto a subject's ear in different
locations. It can be difficult to repeatedly find the position in
which such a sensor works best. In some cases, it is necessary to
try several times before a satisfactory output signal can be
obtained. Earlobe clips can be pulled off with relative ease.
Current earlobe sensors do not always stay fixed on a subject's ear
but may move over time relative to a desired sensing location. This
can cause the quality and fidelity of the sensor output signals to
vary over time. Movements of the sensors may themselves create
artifacts in the sensor output signals, further degrading output
signal quality and fidelity.
Some sensors are designed to be inserted into a subject's ear
canal. Thorgersen, U.S. Pat. No. 6,080,110 describes such a sensor.
Such sensors have the disadvantages that they occlude the subject's
ear canal and can be uncomfortable if kept in place for too
long.
There is a need for ear sensors which ameliorate at least some of
the disadvantages of current ear sensors. There is a particular
need for ear sensors capable of generating quality, robust and
stable pulse signals at a subject's ear.
SUMMARY OF THE INVENTION
The invention relates to methods and apparatus for obtaining
signals, such as pulse signal, from a sensor which interfaces to
the ear of a subject. The sensor is held in place in a sensor
assembly which includes a projection. The projection extends into
the concha of a subject's ear.
One aspect of the invention provides an ear sensor assembly. The
ear sensor assembly comprises a projection insertable into the
concha of a subject's ear and a clip connected to the projection.
The clip comprises a first part biased toward a second part. The
ear sensor assembly comprises a sensor on at least one of the first
and second parts of the clip. The sensor assembly may comprise a
pulse-oximetry-type sensor, for example.
Another aspect of the invention provides an ear sensor assembly
comprising a sensor holder. The sensor holder includes a projection
insertable into a subject's concha and a clip located to grasp a
lobule of the subject's ear when the projection is inserted into
the concha. The sensor assembly also comprises a sensor supported
by the sensor holder. The sensor is located to sense a
physiological characteristic, for example a pulse signal at a
location on the subject's ear.
Another aspect of the invention provides an ear sensor comprising
grasping means for grasping a subject's ear, the grasping means
including sensor support means for supporting a sensor in a
location proximate a lobule of the subject's ear; and, holding
means for preventing the grasping means from slipping off the
subject's ear, the holding means are connected to the grasping
means. The grasping means, sensor support means and holding means
may have any of the various structures described herein as well as
equivalents thereof.
Further aspects of the invention and features of specific
embodiments of the invention are described below.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate non-limiting embodiments of the
invention,
FIG. 1 is a view of the outer ear showing a preferred location for
a pulse-oximetry-type sensor;
FIG. 2 is a side view of a sensor assembly according to one
embodiment of the invention;
FIG. 3 is a cross section of the sensor assembly of FIG. 2 in place
on a subject's ear;
FIG. 4 is a side elevation view of the sensor assembly of FIG. 2 in
place on a subject's ear;
FIG. 5 is an isometric view of a sensor assembly according to an
alternative embodiment of the invention;
FIG. 6 is a side elevation view of the sensor of FIG. 5 in place in
a subject's ear;
FIG. 7 is a cross sectional view of the sensor of FIG. 5 in place
in a subject's ear;
FIG. 8 is another cross sectional view (in a plane medially
displaced from the cross section plane of FIG. 7) of the sensor of
FIG. 5 in place in a subject's ear;
FIGS. 9A through 14C illustrate various alternative configurations
for projections of sensor assemblies according to embodiments of
the invention;
FIGS. 15A, 15B and 15C are respectively a side elevation, a front
elevation and a bottom plan view of a part that may be added to a
conventional clip-on sensor assembly to provide a sensor assembly
according to the invention.
DESCRIPTION
Throughout the following description, specific details are set
forth in order to provide a more thorough understanding of the
invention. However, the invention may be practiced without these
particulars. In some cases, well known elements have not been shown
or described in detail to avoid unnecessarily obscuring the
invention. Accordingly, the specification and drawings are to be
regarded in an illustrative, rather than a restrictive, sense.
This invention provides ear sensor assemblies. An ear sensor
assembly according to the invention has a grasping portion that
grasps a subject's ear, typically on the subject's earlobe, and a
holder portion which projects into the concha of the subject's ear.
The holder portion may help to accurately locate the sensor, to
resist forces which could otherwise undesirably pull or knock the
sensor assembly off of the subject's ear, and/or to retain the
sensor assembly so that the sensor stays in a desired position
relative to the subject's ear.
FIG. 1 shows a human outer ear. The ear has a downwardly-descending
lobule 30 which extends upwardly to just below the rim of a concha
31. A tragus 32 and an anti-tragus 33 project over concha 31. The
inter-tragic incisure 34 is a portion of the ear which extends
along the rim of concha 31 and separates tragus 32 from anti-tragus
33. The antihelix 35 is a portion of the ear which extends along
the rim of concha 31 posterior to anti-tragus 33. The inferior
portion 36 of concha 31 is called the cavum conchae. Concha 31 has
an inferior wall 37. Wall 37 typically extends more or less in a
plane which is roughly perpendicular to lobule 30.
FIG. 2 shows a sensor assembly 10 according to an illustrative
embodiment of the invention. Sensor assembly 10 comprises a sensor
12. In the illustrated embodiment, sensor 12 has two parts. A first
part 12A is intended to contact the lateral side of a subject's
earlobe. A second part 12B is intended to contact the medial side
of the subject's earlobe. Parts 12A and 12B may provide mechanisms
for making any of a variety of types of physiological measurements.
For example, sensor 12 may be a transmission type pulse oximetry
sensor in which one of parts 12A, 12B transmits optical radiation
at one or more wavelengths and the other one of parts 12A, 12B
receives the optical radiation after it has passed through a
portion of the subject's outer ear.
The inventors have determined that a region 38 of lobule 30 close
to anti-tragus 33 is particularly good for detecting pulse signals
using a pulse-oximetry type sensor. In preferred embodiments of the
invention, sensor assembly 10 holds sensor 12 in contact with
region 38 of a subject's ear. The invention is not limited to such
embodiments, however. In some embodiments a notch 22 accommodates
the anti-tragus and helps hold sensor assembly 10 in a desired
position on a subject's ear.
Parts 12A and 12B are mounted on opposed arms of a U-shaped clip
14. Clip 14 presses sensor parts 12A and 12B toward one another. In
the illustrated embodiment, clip 14 comprises an outer part 14A
which carries sensor part 12A and an inner part 14B which carries
part 12B. Clip parts 14A and 14B are coupled together by a hinge
which includes pin 16. A spring (not shown) or other suitable bias
means biases sensor parts 12A and 12B toward one another. As clip
14 performs the function of grasping the subject's ear, clip 14 may
be termed a grasping means. As outer part 14A and/or inner part 14B
perform the function of supporting sensor parts (12A and 12B), the
parts may be termed sensor support means.
Clip 14 provides ear-contacting surfaces 15. In the illustrated
embodiment, ear-contacting surfaces 15 are outer surfaces of pads
17 which are disposed on clip parts 14A and 14B away from hinge pin
16. Sensor parts 12A and 12B are disposed within pads 17. A cable
18 provides a path for carrying signals to and from sensor 12.
Cable 18 may carry conductors for supplying driving current to one
or more light sources of sensor 12 and conductors for carrying
signals from sensor 12 to a control unit (not shown).
A projection 20 is coupled to clip 14. In the illustrated
embodiment, projection 20 projects in an inward direction from an
end 14C of outer clip part 14A. Projection 20 is located and
dimensioned to project into the concha of a subject's ear when
sensor 12 is in a desired position on a subject's ear. The desired
position coincides with region 38 (see FIG. 1) in some embodiments.
A lower face of projection 20 projects at an angle of approximately
90 degrees.+-.20 degrees to a plane of sensor 12. As projection 20
serves the function of better holding ear sensor assembly 10 to a
subject's ear, projection 20 may be termed a holding means.
FIGS. 3 and 4 show sensor assembly 10 in position on a subject's
ear. It can be seen that clip 14 positions sensor 12 over region
38. Sensor parts 12A and 12B press against opposed sides of the
subject's lobule 30. Projection 20 projects into the subject's
concha 31 and contacts wall 37. A forward-projecting member 25,
(shown in dotted outline in FIG. 4) may optionally be provided to
prevent sensor assembly 10 from slipping toward the subject's face.
Another member 25 may project from the other side of clip 14 for
use when the sensor assembly is being used on the subject's other
ear.
As shown in FIG. 3, sensor assembly 10 has a notch 22 at the
intersection of projection 20 and clip 14. Notch 22 accommodates
the subject's anti-tragus 33. A lower face 20A of projection 20
contacts wall 37. A side face 20B may be shaped to contact the
portion of the wall of the concha which is adjacent to inter-tragic
incisure 34. The shaped side face of projection 20 may have a
convex curvature, though it is not limited to this shape.
Projection 20 projects inwardly into the subject's concha past
outer sensor part 12A and preferably past inner sensor 12B. In some
embodiments, projection 20 projects inward a distance in the range
of 7 mm to 14 mm from the plane of the outside of the subject's
lobule 30 (i.e. a plane passing through the face of outer sensor
part 12A).
As shown in FIG. 4, a line 39 extending between the center of
region 38 and the part of concha 31 closest to the center of region
38 is typically at an angle of 30.degree. to 50.degree. to the
vertical (with vertical referenced to the subject's head).
Sensor assembly 10 may be symmetrical, as shown in FIG. 2, in which
case it may be used with either a subject's right or left ear. In
this case, an axis of symmetry 24 of sensor assembly 10 may be
oriented so that it extends generally along line 39 when the sensor
assembly 10 is properly in place on a subject's ear.
The ear-contacting surfaces of sensor portions 12A and 12B and
projection 20 may be made of, or coated with, material which
provides a high coefficient of friction with the skin of the ear.
The high-friction material may be on a replaceable cover or may be
a part of sensor assembly 10 not intended to be removed in normal
use. The high-friction material may comprise, for example, rubber,
silicone, another suitable elastomer, or the like. The
high-friction material may comprise an elastomer having a tacky
surface.
The ear-contacting surfaces of sensor assembly 10 may be
significantly larger than required for operation of sensor 12 to
provide large contact areas with inner and outer surfaces of lobule
30. Sensor portions 12A and 12B may be offset toward projection 20
in the ear-contacting portions so that they line up with region
38.
FIGS. 5 through 8 show a sensor assembly 10' according to an
alternative embodiment of the invention. In FIGS. 5 through 8,
features of sensor assembly 10' which correspond to features of the
sensor assembly 10 depicted in FIGS. 2, 3 and 4 are identified by
the same reference numerals as are used in FIGS. 2, 3 and 4,
modified by the addition of a "prime" symbol--'. Sensor assembly
10' differs from sensor assembly 10 primarily in that projection
20' is apertured. In the illustrated embodiment, projection 20'
comprises a partial ring, specifically a projecting half-ring 21'.
Half-ring 21' may be coated with a material having a high
coefficient of friction. In some example embodiments, half-ring 21'
has a radius in the range of 3.5 mm to 6 mm. In some example
embodiments, half-ring 21', has a thickness in the range of about
1.5 mm to 3 mm.
There are many alternative configurations for projection 20. Some
possible alternative configurations are shown in FIGS. 9A through
14C. FIGS. 9A, 9B and 9C show a projection 20-1 which is similar to
the projection 20 shown in FIG. 1 except that some
non-ear-contacting surfaces are cut away. FIGS. 10A, 10B and 10C
show a projection 20-2 which comprises a generally flat panel 50
projecting inwardly from clip 14. Panel 50 may have a rounded
triangular shape as shown. FIGS. 11A, 11B and 11C show a projection
20-3 which comprises a generally flat panel 52 penetrated by an
aperture 53. A projection may comprise two or more projection
members, one or more of which extends into the concha of a
subject's ear. FIGS. 12A, 12B and 12C show a projection 20-4 which
comprises a pair of curved pin projection members 54. In some
example embodiments the curved pin projection members 54 have
lengths in the range of 8 mm to 16 mm. FIGS. 13A, 13B and 13C show
a projection 20-5 comprising a pair of straight pin projection
members 55. In some example embodiments, pin projection members 55
have lengths in the range of 6 mm to 9 mm. FIGS. 14A, 14B and 14C
show a projection 20-6 which is similar to projection 20-2 except
that it is convex on its bottom side 56.
Projection 20 may be formed as a unitary part with at least the
outer part 14A of clip 14, e.g. in an injection molding process. In
the alternative, projection 20 and outer part 14B of clip 14 may be
assembled from two or more smaller parts. In one embodiment, sensor
assembly 10 is assembled by attaching a projection 20 to an
existing clip-on ear sensor. FIGS. 15A, 15B and 15C show an example
of a part 60 which includes a projection 20'' on an arm 62. Part 60
may be attached to a suitable conventional clip-on ear sensor using
a suitable adhesive, welding, or in any other suitable manner to
provide a sensor assembly according to the invention.
Where a component (e.g. an assembly, device, sensor etc.) is
referred to herein, unless otherwise indicated, reference to that
component (including a reference to a "means") should be
interpreted as including as equivalents of that component any
component which performs the function of the described component
(i.e., that is functionally equivalent), including components which
are not structurally equivalent to the disclosed structure which
performs the function in the illustrated exemplary embodiments of
the invention.
As will be apparent to those skilled in the art in the light of the
foregoing disclosure, many alterations and modifications are
possible in the practice of this invention without departing from
the spirit or scope thereof. For example, Sensor assemblies
according to the invention may include single-part sensors in
addition to, or instead of, the two-part sensors described above.
Sensor assemblies according to the invention may include sensors
with any number of parts or any number of means of detecting
physiological characteristics, mounted on either or both sides of
clip 14. Instead of coupling clip parts 14A and 14B with a hinge
defined by a pin 16, as shown in FIG. 2, parts 14A and 14B could be
connected by a section of material which is flexible enough to
permit parts 14A and 14B to be moved toward and away from one
another. In such embodiments, the section of material may itself be
resilient so as to serve as a means for pressing parts 14A and 14B
toward one another. A sensor assembly according to the invention
may be asymmetrical. Different sensor assemblies may be provided
for use on left and right ears. Projection 20 could be coupled to
the rest of the sensor assembly in such a way as to allow movement
(for example, pivoting) relative to the sensor assembly. The
projection 20 could be movable between a first position for use in
a subject's left ear and a second position for use in a subject's
right ear. The scope of the invention is defined by the following
claims.
* * * * *